Response of Guar (Cyamopsis tetragonoloba L.) to Planting Date and Row Spacing in Jiroft

IntroductionThe highest concentration of protein is found in plant-based sources, whereas animal protein production tends to be more challenging and costly compared to plant-derived proteins. Within plant sources, legumes emerge as a primary reservoir of protein. A notable proportion of protein compounds within legumes boast relatively high nutritional value. The amount of protein in most plants of the legume family, including beans, is reported between 18 and 32%. guar or cluster bean (Cyampsis tetragonoloba (L.) Taub.) is an annual plant from the legume family, which is cultivated in dry plains as an alternative crop due to its high tolerance to drought and salt conditions. This plant, like most legumes, is important in the balance of soil mineral elements in agricultural systems due to its ability to symbiosis with nitrogen-fixing bacteria. Planting date and optimal plant density are two effective factors to achieve the potential performance of plants. Considering the importance of guar as an edible, industrial, fodder and medicinal product, it seems necessary to conduct research on the growth response of this plant to management factors, especially the date and density of plant planting. The present study was conducted with the aim of investigating the effect of planting date and row spacing on guar plant as an alternative plant for the climatic conditions of southern Kerman and other similar climates, in order to achieve the highest yield and grain quality. Materials and Methods The experiment was carried out as split plots based on the completely randomized blocks design with three replications in the research farm of South Kerman Agricultural and Natural Resources Research and Education Center (Jiroft) in two years 2018-2019. Jiroft region has a latitude of 57 degrees and 32 minutes north and a longitude of 28 minutes and 32 degrees east and is located at an altitude of 628 meters above sea level. The experimental treatments include planting date as the main factor in six levels (10 and 25 May, 9 and 24 June, 9 and 24 July) and seed planting intervals as secondary factors in four levels (20, 30, 40 and 50 cm). Results and DiscussionThe results showed that the maximum dry weight of leaves and stems, the number of leaves in the secondary stem, the height of the plant and the length of the pod were observed on the date of 24 June and the row spacing was 50 cm, and in all planting dates, increasing the row spacing led to an increase in the mentioned traits. The comparative analysis of average planting dates reveals that the highest metrics were achieved on June 9th. This includes a 43% increase in the number of pods per plant, a 23% increase in the number of grains per pod, a 66% increase in biological yield, a 45% increase in grain yield, and an 18% increase in harvest index. The highest leaf surface index (15%) and number of leaves in the main stem (91%) was observed on the 24 June. In general, with the delay in planting after early June (9 June) to late June (24 June), the yield and yield components of guar gradually decreased and reached the lowest value. The results comparing the mean effect of row spacing showed the highest number of pod per plant and seeds per pod at 50 cm row spacing, but the highest grain yield was obtained at 30 and 40 cm row spacing. Conclusions In general, among the planting dates, guar planting in June to early July in Jiroft region is the best planting date. While, early planting (May) and late planting (late July) were not favorable for guar and led to a decrease in plant yield. Therefore, in order to obtain the best yield and agronomic characteristics of guar plant in the south of Kerman province and similar conditions, it is recommended to cultivate this plant from early June to early July and at a row distance of 30 to 40 cm, because in the mentioned dates and row spacing, the plant makes the best use of environmental factors and with the reduction of competition between the plants, its performance and components increase Because.